When I ride my bike, depending on which route I take, there are bike lanes and there are not - both routes take the same amount of time/distance, the only difference is the presence (or lack thereof) of bike lanes.

I doubt there would be a "right" answer to that (except "it depends..."), but sure the issue deserves some discussion...
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heltonbikerMar 5 '12 at 16:20

It's also important to define what makes something "more dangerous"--in particular the comparison of frequency vs severity. I know some roads rarely have accidents, but when they do, they're almost always fatal. Other roads have much more frequent accidents, but the damage is (relatively) minor. Is there a good way to compare those two?
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prototoastMar 6 '12 at 5:16

5 Answers
5

In general, bike lanes (and other bike facilities) appear to be safer. Of course this is not always the case, but the general trend is that bike facilities, including lanes, tend to improve safety in the cycling environment.

A review of 23 studies on bicycling injuries found that bike facilities (e.g. off-road paths, on-road marked bike lanes, and on-road bike routes) are where bicyclists are safest.

On-road marked bike lanes were found to have a positive safety effect in five studies, consistently reducing injury rate, collision frequency or crash rates by about 50% compared to unmodified roadways [61,62,65-67]. Three of those studies [61,66,67] found a similar effect for bike routes. One study [63] found that there was an increase in crash rates in the year following installation of marked bike lanes on a major road, especially for a section counter to on-road traffic flow, but this effect was not sustained over the long term.

Although the effect of infrastructure design on cyclist safety was first studied more than three decades ago, the literature on the topic remains remarkably sparse. This review highlights opportunities for more detailed and controlled studies of infrastructure and cycling injuries.

...Results. Installation of bicycle lanes did not lead to an increase in crashes, despite the probable increase in the number of bicyclists. The most likely explanations for the lack of increase in crashes are reduced vehicular speeds and fewer conflicts between vehicles and bicyclists after installation of these lanes.

When protected bike lanes are installed, injury crashes for all road users (drivers,
pedestrians, cyclists), typically drop by 40 percent and by more than 50 percent in
some locations

Based on personal experience, I think that bike lanes are safer when well designed and maintained. I normally use available bike lanes in my city; however, with the caveat being that I make every attempt at maintaining awareness of the surroundings. I'll just say that bike lanes are pretty much useless for the oblivious cyclist; otherwise bike lanes are a good idea.

Observations (so my personal opinion):

Bike lanes and paths are more or less dangerous depending on the location. Some cities/countries have good cycling infrastructure and some do not.

Oblivious cyclists are always in danger. So, there's a point to be made that cyclists need to be highly attentive to conditions at all times.

Bikes Belong has links to a plethora of bicycling research and statistics.

The two articles you link call bike lines dangerous, but in the first article the dangers come from bad maintenance and some poor design choices, and in the second article the dangers come from abuse of the bike lane by others. This muddies the issues, but highlights a problem with your question, which is: It really depends on the situation.

If the bike lane is poorly maintained, crosses a lot of busy intersections, is narrow, and is poorly separated from the road and your other route is along a very quiet very wide country road with almost no intersections then obviously the non-bike lane option is a lot safer.

In my experience the on-road safety for cyclists, regardless of the availability of bike lanes depends on:

Traffic density

Amount of space available

Visibility conditions, especially at intersections

Quality of the road

How accustomed other traffic participants are to sharing the road with cyclists.

Bike lanes help improve safety where they separate bikes from other traffic, but if bikes and other traffic later mix again (at intersections) then obviously the chances of the other traffic not thinking of the bikes increase, and thus the chance of accidents increases. This is what the german study linked by thiton highlights. In my experience the "danger" in bike lanes is mostly a danger of the place where the bike lane ends. And bike lanes are of course more likely to end in places where installing the bike lanes was not a very popular option in the first place.

I have cycled all over europe, and there are a lot of cities where, at some point, environmental concerns, health concerns, and what have you prompted city administrators to start building bike lanes. However, in countries where there is no cycling culture you will see that the bike lanes simply disappear whenever it would be even slightly inconvenient for other road users to build a bike lane. Every bike-lane end creates a situation that is generally more dangerous than it was before the bike lane was installed at that point in the route. If you build enough continuous bike lanes you make your streets safer for cyclists, but if all you do is add bike-lane-endings all over the place the route probably become more unsafe for cyclists.

so there you have it. It depends on the specific bike lane. Use your judgement. Maybe try both routes slowly a few times to see how often you encounter risky situations on either, before doing them at race speeds.

Yes, and no. Maybe. John Forester & co did some studies about 30-35 years ago that suggested that bike paths (primarily in the eastern US) were more dangerous. But bike lane/path technology has improved since then, and a lot depends on the particular circumstances.

IIRC, the biggest hazard was at side streets and driveways, where the motorist was apt to cross the bike path without yielding. (This problem would presumably be somewhat less likely with bike lanes that are only slightly separated from the driving lanes.)

In general, accidents at intersections are something like 50 times more common that "overtaking" accidents.

Another problem can be pedestrians, deliveries etc loitering in or trespassing onto the bike lane, more than they would on a road.
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ChrisWMar 5 '12 at 17:25

There are a number of potential problems with bike paths, though less with bike lanes (but still more than if "playing in traffic"): Pedestrians, dogs, other bikes, sudden twists of the path, odd obstacles in the lane such as fire hydrants, utility poles, bollards, etc.
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Daniel R HicksMar 5 '12 at 21:42

2

Downvoted - You cite a 30+ year old study and provide only anecdotal reasoning. Also, your last sentence is wrong (According to US Dept of Transportation data).
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user313Mar 7 '12 at 2:49

@wdypdx22 -- Maybe the data's improved in 30 years, but used to be that the DOT data was badly skewed for a number of reasons.
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Daniel R HicksMar 7 '12 at 14:00

2

Not arguing, but one of the problems with earlier government data was that bike accidents that didn't both involve a motor vehicle and result in death or severe injury never made it into the government stats. So lots of "minor" TAs were omitted, as were bicycle-bicycle, bicycle-pedestrian, and bicycle-fixed object injuries. Advocates had to actually stake out emergency rooms to collect better data.
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Daniel R HicksMar 8 '12 at 23:45

However, there are plenty of styles for bike lanes, and much difference between countries, and I'd think that the low total number of accidents considered (roughly 1000) is sufficient to give a general answer. So, handle results with care.

Also, the study appears to about "paths" and not "lanes". Is there a difference in Germany between paths and lanes? An issue in this type of study is that the terminology is poorly defined.
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user313Mar 6 '12 at 23:00

@wdypdx22 - Is that from the Google translation? (It says the same for me.) Anyone here read German? Does the article talk about bike lanes on the road or separate bike paths?
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Neil FeinMay 6 '12 at 2:51

I don't have any statistics to support my point but I have been commuting to work regularly on my bike in London for over fifteen years. In my experience most roads are safer than dedicated bike lanes. This may sound counter intuitive but there are definite issues around using cycle lanes, especially those on quiet roads or those that share space with pedestrians. Clearly there are exceptions. Cycling on a motorway for example is not only illegal but also dangerous for cyclists.

Clearly, when cycling on the road you need to take care that you are observant of other vehicles (including cyclists and pedestrians who want to cross the road) but as long as you are doing this and you ensure you are visible and not just to vehicles behind you but in front of you (if you can't see the wing mirror of a lorry / bus in front of you what chance do they have of seeing you).

I do use cycling lanes but find I need to take even greater care when using them, especially those on quieter routes for the simple reason that on a quieter route being a cyclist means that your mode of transport is in itself very quiet. Pedestrians and other cyclists don't hear you coming. You need to be aware of this.

My simple advice though is that your safety is your responsibility first and foremost. Don't jump lights, avoid weaving through traffic and make sure you are visible at all times. Be aware of other road / pavement users and try to anticipate problems rather than assume you have the right to cycle as fast as you like. Stick to those principles and you will be safe.